Optical fiber grating sensing and demodulating device based on dual wavelength beat frequency technology

Abstract

The invention discloses an optical fiber grating sensing and demodulating device based on the dual wavelength beat frequency technology. The optical fiber grating sensing and demodulating device is characterized by comprising an optical amplifier, a sensing element, a tunable band-pass filter, a coupler, an optical detector and a spectrum analyzer. The sensing element is a Fabry-Perot cavity manufactured based on a fiber bragg grating, the operating wavelength of the tunable band-pass filter is the same as the wavelength of the reflected wave of the Fabry-Perot cavity, the operating bandwidth of the tunable band-pass filter is more than delta lambda and less than double of delta lambda, the lambda is the wavelength of the reflected wave of the Fabry-Perot cavity, and the delta lambda is the spectrum oscillating period of the Fabry-Perot cavity. The optical fiber grating sensing and demodulating device has the advantages of realizing demodulation of a single longitudinal mode or multiple longitudinal mode ring cavity laser sensors, overcoming the limit that the existing sensor based on the beat frequency technology needs the single longitudinal mode feature, reducing the complexity of the system and facilitating the manufacturing, the application and the popularization of the existing sensors based on the beat frequency technology.

Description

technical field [0001] The invention relates to the field of physical sensing, in particular to a physical sensor based on fiber bragg grating technology and beat frequency technology. Background technique [0002] Since the first generation of low-loss multi-film optical fiber produced by Corning Corporation of the United States in the 1970s, the optical fiber has been widely used in the fields of communication and sensing after more than 40 years of development. As early as 1978, K.O.Hill et al. in Canada first used an argon ion laser to write fiber Bragg gratings in a germanium-doped optical fiber. In 1989, W.W.Morey et al. studied the temperature and strain sensing characteristics of fiber gratings for the first time. , the grating reflection wavelength temperature sensitivity and strain sensitivity are respectively 1.1x10 -2 nm / με and 1.2x10 -3 After nm / με, fiber grating-based sensing technology has gradually been applied in many fields. [0003] As an important devi...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a fiber grating sensing demodulation device based on dual-wavelength beat frequency technology, which overcomes the defect of high manufacturing cost of lasers in existing sensing measurements

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